Open Journal of Stomatology, 2013, 3, 287-291 OJST
doi:10.4236/ojst.2013.35048 Published Online August 2013 (http://www.scirp.org/journal/ojst/)
Clinical, radiological and histological diagnoses of
periapical periodontitis spreading to the adjacent tooth:
A case of endodontic failure
Luigi Cianconi, Manuele Mancini
Department of Restorative Dentistry and Endodontics, University of Rome “Tor Vergata”, Rome, Italy
Received 23 May 2013; revised 24 June 2013; accepted 15 July 2013
Copyright © 2013 Luigi Cianconi, Manuele Mancini. This is an open access article distributed under the Creative Commons Attri-
bution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly
cited.
ABSTRACT
Aims: This article describes the apical infection in
endodontically treated tooth 4.5 that spread to adja-
cent tooth 4.4. Case Report: A 52-year-old woman
was referred for the presence of radiolucency extend-
ing from tooth 4.5 and mental foramen. Spontaneous
symptoms were present. Tooth 4.5 showed poor-qua-
lity endodontics. The vitality of tooth 4.4 was negative,
even though no mechanical trauma had been re-
ported, nor was caries present. Both teeth were sensi-
tive to percussion. En dodo ntic re-treatment of 4.5 and
endodontic treatment of 4.4 were performed in a sin-
gle visit. A large amount of endodontic sealer sque-
ezed mesially from the root of tooth 4.5, where a par-
tial horizontal root fracture was hypothesized. 6-, 12-,
and 18-month radiographic follow-ups, by both peri-
apical and cone-beam computed tomography (CBCT)
analyses, showed incomplete osseous healing. CBCT
excluded root fracture on 4.5. Local symptoms were
still present. Clinical and radiological conditions led
to extractions, and a cystic lesion was enucleated for
histopathologic analyses. Histopathologic diagnosis was
a periapical cyst. The supposed partial horizontal
root fracture of 4.5 was actually a large lateral canal.
Although the root canal treatments followed high
standards in terms of quality, a persistent chronic in-
fection developed histologically. The cystic lesion was
one consistent reason for the unsuccessful healing of
4.5.
Keywords: Apical Periodontitis; Apicoectomy;
Follow-Up; CBCT; Cyst; Lateral Canal
1. INTRODUCTION
The diagnosis of periapical lesions is usually based on
clinical and radiographic findings, which are empirical
methods. Nevertheless, endodontists commonly strive to
make a definitive diagnosis of periapical pathologies of
inflammatory origin. A final diagnosis can be achieved
by histopathological examination of the tissues, which is
not practical in cases of non-surgical treatment. Pulpal
necrosis and apical lesion deployment occur only when
oral microbiota exists [1,2]. Non-surgical root canal treat-
ment has a very high success rate in teeth with apical
periodontitis [3,4]; therefore, a n ecrotic tooth with apical
periodontitis generally receives non-surgical root canal
treatment alone. Periapical radiographs provide impor-
tant information about the development, reduction, and
persistence of apical periodontitis, as well as indispensa-
ble data from which treatment decisions can be made.
Radiographically, inflammatory periapical pathologies
present as a radiolucent area, with or without a well-de-
fined periphery simulating a cortex. The presence of a
radiopaque cortex, displacement of adjacent structures,
and diameter exceeding 9.5 mm usually allow the clini-
cian to diagnose a periapical cyst [5,6]. However, the ra-
diographic image, as a shadow, has the elusive qualities
of all shadows. It is a two-dimensional representation of
a three-dimensional object. New imaging modalities have
been used as diagnostic tools in dental radiology. Cone-
beam computed tomography (CBCT) produces detailed
high-resolution, three-dimensional images of oral struc-
tures, which may allo w bone lesions to be detected at an
early stage [7,8]. According to the literature, imaging me-
thods are useful tools for the diagnosis of periapical le-
sions [9], but are not sufficiently accurate to be used as a
standard criterion for diagnosis, as is, in this case, the his-
tological examination of the lesion by microscopy [10].
2. CASE HISTORY
A 52-year-old woman was referred to for the presence of
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L. Cianconi, M. Mancini / Open Journal of Stomatology 3 (2013) 287-291 288
radiolucency extending from the apex of tooth 4.5 and
the mental foramen. The patient’s medical history was
non-contributory, and spontaneous symptoms (burning
sensation and right lower lip numbness) were reported.
Nor intraoral neither extraoral swelling was present. A
mild response to percussion testing of teeth 4.5 and 4.4
was present. Radiographic examination revealed an in-
adequately treated root canal associated with a large
radiolucent periradicular lesion extend ing from the ap ical
to the mesial aspect of the root of tooth 4.5 and the apex
of tooth 4.4 (Figure 1(A)). Radiopaque root canal filling
material was observed at the apical segment of the canal,
and radiolucent post-endodontic core material was visi-
ble at the coronal third of the canal. Cold, warm, and
electric pulp vitality testing on tooth 4.4 was negative.
Endodontic re-treatment of tooth 4.5 and endodontic
treatment of tooth 4.4 were performed in a single visit,
needing no intracanal medicaments, as described by Su
et al. [11]. Antibiotics were not prescripted because nor
swelling neither purulent exudate was noticeable.
2.1. Tooth 4.5
After removal of the provisional prosthodontic coronal
restoration, followed by rubber dam isolation, access to
the coronal cavity was completed. The operative field
was decontaminated with tincture of iodine (10% w/v)
(Betadine; Meda Pharma SpA, Milano, Italy), and an
ultrasound Start-X tip #3 (Dentsp ly Maillefer, Ballaigues,
Switzerland) was used to retrieve the carbon-fiber post
luted at the coronal part of the canal. The root canal was
instrumented as follows: Gates-Glidden burs (sizes #2, 3,
and 4) were used to enlarge the coronal and middle seg-
ments of the root canal. Hand SS K-type files (Dentsply
Maillefer) were used until the working length—meas-
ured by deducting 0.5 mm from the measurement on the
‘‘APEX’’ mark of #15 K-file (Propex II; Dentsply Mail-
lefer)—was reached. Apical preparation was performed
with a ProTaper F4 file. Apical patency was maintained
throughout the pro cedur es by a #20 K-type file. Vigorous
irrigation with 5.25% 37˚C NaOCl was performed after
each file. The smear layer was removed by the use of 5
mL 17% EDTA followed by 5.25% 37˚C NaOCl. The
root canal was dried with sterile paper-points and filled
by the Continuous Wave Technique with gutta-percha
and AH Plus Sealer (Dentsply DeTrey, Konstanz, Ger-
many). A large lateral canal, initially judged as a partial
horizontal root fracture, was revealed after obturation
(Figure 1(B)). The coronal cavity was restored with
composite.
2.2. Tooth 4.4
Endodontic access to the pulp chamber was gained with
a round diamond-coated bur (Dentsply Maillefer). Pulp
canal debris was removed from the coronal third of the
canal with a #4 Gates Glidden bur. We measured the
working length by deducting 0.5 mm from the measure-
ment on the ‘‘APEX’’ mark of #15 K-file (Dentsply
Maillefer). The tooth was shaped by means of ProTaper
Ni-Ti rotary instruments (Dentsply Maillefer), according
to the manufacturer’s instructions, until the F4 file
reached the working length. Apical patency was main-
tained throughout the procedures by a #20 K-type file.
Vigorous irrigation with 5.25% 37˚C NaOCl was per-
formed after each file. The smear layer was removed by
the use of 5 mL 17% EDTA followed by 5.25% 37˚C
NaOCl. The root canal was dried with sterile paper-
points and filled by the Continuous Wave Technique with
gutta-p erch a and AH P lus S ealer (Den tsp ly DeTrey). The
coronal cavity was restored with composite (Figure
1(B)).
2.3. Follow-Up
Six-month radiographic follow-up showed incomplete
osseous healing. Symptoms were still present on both
teeth. Most of the sealer extruding periapically and later-
ally was not resorbed (Figure 1(C)). Local clinical symp-
toms (burning sensation and lip numbness) were still
present. The periapical X-ray 12 months after endodontic
therapies showed a radiolucent periapical lesion; there-
fore, a CBCT analysis was prescribed to exclude a partial
horizontal root fracture on tooth 4.5 (Figure 1(D)). The
sealer extruding laterally on tooth 4.5 was still visible,
whereas only minimal residual sealer could be seen on
the apical aspect of tooth 4.4. At this stage no further
therapies were scheduled, in accordance to studies show-
ing no benefits would have been obtained [3,4]. In the
follow-up appointment 18 months after re-treatment/treat-
ment, spontaneous clinical symptoms were present, teeth
were still symptomatic, and a new CBCT analysis re-
vealed periradicular radiolucency suggestive of persis-
tent disease (Figure 2(A)). The time elapsed since the
end of the therapy, as described by some Authors [3,4],
the good quality of the re-treatment, and the presence of
symptomatic pain led us to perform apicoectomy surgery
on teeth 4.4 and 4.5. The patient participated in the deci-
sion-making process. Treatment planning changed during
surgery, however. The dental surgeon decided to extract
both teeth for two reasons: first, because the cystic lesion
included tooth 4.4 and was very close to the mental fo-
ramen (Figure 2(B)), thus explaining the patient’s con-
tinuous and spontaneous pain; and second, because the
root remaining after apicoectomy behind the supposed
partial fracture of root 4.5 would have not withstood
post-endodontic treatment and occlusal load. The cystic
esion was proc essed for histopathologic analyses. l

L. Cianconi, M. Mancini / Open Journal of Stomatology 3 (2013) 287-291 289
Figure 1. (A) Periapical x-ray showing a large radiolucent periradicular lesion extending
from the apical to the mesial aspect of the root of tooth 4.5 and the apex of tooth 4.4; (B)
Periapical X-ray showing a large lateral canal on tooth 4.5 after the endodontic obturation; (C)
Six-month radiographic follow-up showed incomplete osseous healing. Most of the sealer
extruded periapically and laterally on tooth 4.5 was not resorbed; (D) Twelve-month radio-
graphic follow-up: CBCT analysis was prescribed to exclude a partial horizontal root fracture
on tooth 4.5.
3. SPECIMEN ANALYSIS
3.1. Specimen Preparation
Specimens were immediately immersed in 10% neutral
buffered formalin and fixed for 48 hours. Care was taken
to enucleate the lesion still attached to the root tip.
Three-week demineralization was carried out in an aque-
ous solution consisting of a mixture of 22.5% (vol/vol)
formic acid and 10% (wt/vol) sodium citrate. The biopsy
specimen was washed in running water for 48 hours,
dehydrated in ascending grades of ethanol, cleared in
xylene, and infiltrated and embedded in paraffin (melt-
ing point 56˚C) according to standard procedures.
3.2. Histopathological Analysis
The pathology report revealed a fibrous, hyperplastic,
non-keratinized squamous tissue with bony spicules, and
a site of chronic inflammation corresponding to activated
epithelial cell rests of Malassez (Figure 2(C)). The histo-
pathologic diagnosis was a periapical cyst. The supposed
partial horizontal root fracture of tooth 4.5 was actually a
large lateral canal (Figure 2(D)).
4. DISCUSSION
Many authors have demonstrated that from 94% to 99%
of periapical lesions are associated with pulpal disease
and diagnosed as periapical granulomas, cysts, or ab-
scesses [12]. Biopsies of periapical lesions are usually
undertaken for diagnostic affirmation, persistent or atypi-
cal presentations, or for cases with a relevant medical
history [13]. The differential diagnosis of periapical ra-
diolucencies is diverse [14]. Post-treatment apical perio-
dontitis is caused by either persistent or secondary intra-
radicular infection [15]. Micro-organisms that persist
after intracanal procedures of disinfection and manage to
survive in the obturated root canal can cause persistent
infections. Secondary infections are usually caused by
bacteria introduced into the canal via a breach in asepsis
during treatment or via coronal leakage in obturated root
canals exposed to the oral cavity. Post-treatment apical
periodontitis can also be categorized as recurrent (rede-
veloping after having healed) [15]. Recurrent disease
quite often represents a late failure of the endodontic
treatment, and the cause is conceivably related to a new
event arising years after treatment conclusion. Coronal
leakage after tooth fracture or loss of the permanent cor-
onal restoration might be an example of such a new event
[16]. Bacteria causing persistent infections are usually
located in areas unaffected by instruments and antim-
icrobial substances, including lateral canals, apical rami-
fications, and isthmuses [17]. In addition, bacteria may
even remain in the main canal, especially on dentinal
OJST

L. Cianconi, M. Mancini / Open Journal of Stomatology 3 (2013) 287-291 290
Figure 2. (A) Eighteen months CBCT analysis after retreat-
ment/treatment revealed periradicular radiolucency suggestive
of persistent disease; (B) Eightee n months CBCT analysis show-
ing lesion close to the mental foramen; (C) Histopathology image
showing fibrous, hyperplastic, nonkeratinized squamous tissue;
(D) The large lateral canal filled with endodontic sealer on the
mesial aspect of tooth 4.5.
canal walls that remained untouched by instruments [18].
Bacterial invasion of dentinal tubules has also been re-
garded as a potential source of persistent infection [19],
but there is no convincing report on dentinal tubule in-
fection as a cause of post-treatment disease [20].
This article describes a radiolucency involving two
teeth and the failure of non-surgical endodontic root
canal therapies. Tooth 4.5 had necrotic pulp with apical
periodontitis, whereas tooth 4.4 had necrotic pulp with
normal apical tissue. No caries, trauma, or fracture was
observed on tooth 4.4. It was hypothesized that the per-
sistent apical lesion and infection on tooth 4.5 affected
tooth 4.4. Tooth 4.5 did not respond to re-treatment, per-
haps because of coronal leakage or insufficient intracanal
cleaning and shaping at the apical area, which resulted in
an insufficient filling. Bacteria growing in a poor coronal
filling can increase significantly, gain access to the apical
lesion, and continue to inflame and infect the apical tis-
sues [21]. Post-treatment apical periodontitis is primarily
an infectious disease caused by either an intraradicular or
an extraradicular infection [21]. In treated tee th with post-
treatment disease in which the canals were apparently
treated under acceptable standards, bacteria are usually
observed in biofilms colonizing untouched areas of the
main root canal, apical ramifications, lateral canals, and
isthmuses [22]. Although the root canal was instru-
mented up to its terminus, a strong co nc en trat ion (5 .2 5%)
of NaOCl was used for irrigation, a large amount of sealer
was squeezed into a large lateral canal, and the obtura-
tion followed a high standard in terms of quality (apical
length and homogeneity), a persistent chronic infection
still developed histologically. Stashenko et al. [23] show-
ed that apical infections might spread and produce
symptoms when bacteria become stronger than the host’s
defense systems. Also, the anatomical complexities of
the apical area may limit treatment success [24]. One
consistent reason for the unsuccessful healing on tooth
4.5 was the cystic lesion, which expanded laterally to
tooth 4.4 due to the thickness of the cortical bone and the
thin anatomical structure in the lateral teeth of the man-
dible. According to Skaug [25], fluid pressure in odonto-
genic jaw cysts is higher than the atmospheric pressure.
It has been speculated that increased intracystic fluid
pressure might activate the growth of odontogenic jaw
cysts [26]. Large cystic and periapical lesions are dif-
ficult to heal with only non-surgical root canal treatment
[27]. Radiographs (Figures 1(D) and 2(A)) show a well-
defined circumscribed radiolucency with a well-defined
cortical border, which was interrupted by the apex of
tooth number 4.5. During surgery, tissue was found to be
attached to the apex of tooth number 4.5 and needed to
be separated for biopsy. In summary, this rare case shows
that apical infection from one tooth may spread to adja-
cent teeth.
5. CONCLUSION
In this case report, although the root canal treatments
followed high standards in terms of qu ality, the evidence-
based radiological and clinical follow-ups were sched-
uled, a persistent chronic infection developed histologi-
cally. The cystic lesion was one consistent reason for th e
unsuccessful healing of apical-periapical translucency.
REFERENCES
[1] Kakehashi, S., Stanley, H.R. and Fitzgerald, R.J. (1965)
The effects of surgical exposures of dental pulps in germ-
free and conventional laboratory rats. Oral Surgery, Oral
Medicine, Oral Pathology, 20, 340-349.
doi:10.1016/0030-4220(65)90166-0
[2] Sundqvist, G. (1976) Bacteriological studies of necrotic
dental pulps. University of Umea, Umea.
[3] Sjögren, U., Hägglund, B., Sundqvist, G. and Wing, K.
(1990) Factors affecting the long-term results of endo-
dontic treatment. Journal of Endodontics, 16, 498-504.
doi:10.1016/S0099-2399(07)80180-4
[4] Marquis, V.L., Dao, T., Farzaneh, M., Abitbol, S. and
Friedman, S. (2006) Treatment outcome in endodontics:
The Toronto study. Phase III: Initial treatment. Journal of
Endodontics, 32, 299-306.
doi:10.1016/j.joen.2005.10.050

L. Cianconi, M. Mancini / Open Journal of Stomatology 3 (2013) 287-291 291
OJST
[5] McCall, J.O. and Wald, S.S. (1952) Clinical dental ro-
entgenology. 3rd Edition, W.B. Saunders, Philadelphia.
[6] Grossman, L.I. (1950) Root canal therapy. 3rd Edition,
Lea & Febiger, Philadelphia.
[7] Estrela, C., Bueno, M.R., Leles, C.R., et al. (2008) Accu-
racy of cone beam computed tomography and panoramic
and periapical radiography for detection of apical perio-
dontitis. Journal of Endodontics, 34, 273-279.
doi:10.1016/j.joen.2007.11.023
[8] Nair, M.K. and Nair, U.P. (2007) Digital and advanced
imaging in endodontics: A review. Journal of Endodon-
tics, 33, 1-6. doi:10.1016/j.joen.2006.08.013
[9] Simon, J. H. S., Enciso, R., Malfaz, J.M., et al. (2006)
Differential diagnosis of large periapical lesions using
cone beam computed tomography measurements and bi-
opsy. Journal of Endodontics, 32, 833-837.
doi:10.1016/j.joen.2006.03.008
[10] Rosenberg, P.A., Frisbie, J., Lee, J., et al. (2010) Evalua-
tion of pathologists (histopathol ogy) and radiologists (cone
beam computed tomogra phy ) differentiating radic ular cy sts
from granulomas. Journal of Endodontics, 36, 423-428.
doi:10.1016/j.joen.2009.11.005
[11] Su, Y., Wang, C. and Ye, L. (2011) Healing rate and
post-obturation pain of single- versus multiple-visitendo-
dontic treatment for infectedrootcanals: A systematic re-
view. Journal of Endodontics, 37, 125-132.
doi:10.1016/j.joen.2010.09.005
[12] Peters, E. and Lau, M. (2003) Histopathologic examina-
tion to confirm diagnosis of periapical lesions: A review.
Journal of the Canadian Dental Association, 69, 598-
600.
[13] Newton, C.W. (1999) To biopsy or not [letter]. Oral Sur-
gery, Oral Medicine, Oral Pathology, Oral Radiology,
and Endodontics, 87, 642-643.
doi:10.1016/S1079-2104(99)70177-0
[14] Brooks, J.K., Ribera, M.J., Rogers, C.W., et al. (2005)
Radiographic challenges: Report of 5 cases. New York
State Dental Journal, 71, 48-50.
[15] Siqueira Jr., J.F. (2011) Treatment of endodontic infec-
tions. Quintessence Publishing, London.
[16] Ricucci, D. and Siqueira Jr., J.F. (2011) Recurrent apical
periodontitis and late endodontic treatment failure related
to coronal leakage: A case report. Journal of Endodontics,
37, 1171-1175. doi:10.1016/j.joen.2011.05.025
[17] Ricucci, D. and Siqueira Jr., J.F. (2010) Biofilms and
apical periodontitis: Study of prevalence and association
with clinical and histopathologic findings. Journal of En-
dodontics, 36, 1277-1288.
doi:10.1016/j.joen.2010.04.007
[18] Peters, O.A., Schönenberger, K. and Laib, A. (2001) Ef-
fects of four Ni-Ti preparation techniques on root canal
geometry assessed by micro computed tomography. In-
ternational Endodontic Journal, 34, 221-230.
[19] Love, R.M. and Jenkinson, H.F. (2002) Invasion of den-
tinal tubules by oral bacteria. Critical Reviews in Oral
Biology & Medicine, 13, 171-183.
doi:10.1177/154411130201300207
[20] Peters, L.B., Wesselink, P.R. and Moorer, W.R. (1995)
The fate and the role of bacteria left in root dentinal tu-
bules. International Endodontic Journal, 28, 95-99.
doi:10.1111/j.1365-2591.1995.tb00166.x
[21] Siqueira, J.F. (2001) Aetiology of root canal treatment
failure: Why well treated teeth can fail. International
Endodontic Journal, 34, 1-10.
doi:10.1046/j.1365-2591.2001.00396.x
[22] Lin, L.M., Skribner, J.E. and Gaengler, P. (1992) Factors
associated with endodontic treatment failures. Journal of
Endodontics, 18, 625-627.
doi:10.1016/S0099-2399(06)81335-X
[23] Stashenko, P., Wang, C.-Y., Tani-Ishii, N. and Yu, S.M.
(1994) Pathogenesis of induced rat periapical lesions.
Oral Surgery, Oral Medicine, Oral Pathology, 78, 494-
502. doi:10.1016/0030-4220(94)90044-2
[24] Ricucci, D. and Siqueira Jr., J.F. (2008) Anatomic and
microbiologic challenges to achieving success with en-
dodontic treatment: A case report. Journal of Endodon-
tics, 34, 1249-1254. doi:10.1016/j.joen.2008.07.002
[25] Skaug, N. (1976) Intracystic fluid pressure in non-kerati-
nizing jaw cysts. International Journal of Oral Surgery, 5,
59-65. doi:10.1016/S0300-9785(76)80049-X
[26] Oka, S., Kubota, Y., Yamashiro, T., Ogata, S., Ninomiya,
T., Ito, S., et al. (2005) Effects of positive pressure in
odontogenic keratocysts. Journal of Dental Research, 84,
913-918. doi:10.1177/154405910508401008
[27] Nair, P.N. (1998) New perspectives on radicular cysts:
Do they heal? International Endodontic Journal, 31, 155-
160. doi:10.1046/j.1365-2591.1998.00146.x